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diff --git a/src/acceler.c b/src/acceler.c
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+/***********************************************************
+Copyright 1991 by Stichting Mathematisch Centrum, Amsterdam, The
+Netherlands.
+
+ All Rights Reserved
+
+Permission to use, copy, modify, and distribute this software and its
+documentation for any purpose and without fee is hereby granted,
+provided that the above copyright notice appear in all copies and that
+both that copyright notice and this permission notice appear in
+supporting documentation, and that the names of Stichting Mathematisch
+Centrum or CWI not be used in advertising or publicity pertaining to
+distribution of the software without specific, written prior permission.
+
+STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
+THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
+FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
+OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+******************************************************************/
+
+/* Parser accelerator module */
+
+/* The parser as originally conceived had disappointing performance.
+ This module does some precomputation that speeds up the selection
+ of a DFA based upon a token, turning a search through an array
+ into a simple indexing operation. The parser now cannot work
+ without the accelerators installed. Note that the accelerators
+ are installed dynamically when the parser is initialized, they
+ are not part of the static data structure written on graminit.[ch]
+ by the parser generator. */
+
+#include "pgenheaders.h"
+#include "grammar.h"
+#include "token.h"
+#include "parser.h"
+
+/* Forward references */
+static void fixdfa PROTO((grammar *, dfa *));
+static void fixstate PROTO((grammar *, dfa *, state *));
+
+void
+addaccelerators(g)
+ grammar *g;
+{
+ dfa *d;
+ int i;
+#ifdef DEBUG
+ printf("Adding parser accellerators ...\n");
+#endif
+ d = g->g_dfa;
+ for (i = g->g_ndfas; --i >= 0; d++)
+ fixdfa(g, d);
+ g->g_accel = 1;
+#ifdef DEBUG
+ printf("Done.\n");
+#endif
+}
+
+static void
+fixdfa(g, d)
+ grammar *g;
+ dfa *d;
+{
+ state *s;
+ int j;
+ s = d->d_state;
+ for (j = 0; j < d->d_nstates; j++, s++)
+ fixstate(g, d, s);
+}
+
+static void
+fixstate(g, d, s)
+ grammar *g;
+ dfa *d;
+ state *s;
+{
+ arc *a;
+ int k;
+ int *accel;
+ int nl = g->g_ll.ll_nlabels;
+ s->s_accept = 0;
+ accel = NEW(int, nl);
+ for (k = 0; k < nl; k++)
+ accel[k] = -1;
+ a = s->s_arc;
+ for (k = s->s_narcs; --k >= 0; a++) {
+ int lbl = a->a_lbl;
+ label *l = &g->g_ll.ll_label[lbl];
+ int type = l->lb_type;
+ if (a->a_arrow >= (1 << 7)) {
+ printf("XXX too many states!\n");
+ continue;
+ }
+ if (ISNONTERMINAL(type)) {
+ dfa *d1 = finddfa(g, type);
+ int ibit;
+ if (type - NT_OFFSET >= (1 << 7)) {
+ printf("XXX too high nonterminal number!\n");
+ continue;
+ }
+ for (ibit = 0; ibit < g->g_ll.ll_nlabels; ibit++) {
+ if (testbit(d1->d_first, ibit)) {
+ if (accel[ibit] != -1)
+ printf("XXX ambiguity!\n");
+ accel[ibit] = a->a_arrow | (1 << 7) |
+ ((type - NT_OFFSET) << 8);
+ }
+ }
+ }
+ else if (lbl == EMPTY)
+ s->s_accept = 1;
+ else if (lbl >= 0 && lbl < nl)
+ accel[lbl] = a->a_arrow;
+ }
+ while (nl > 0 && accel[nl-1] == -1)
+ nl--;
+ for (k = 0; k < nl && accel[k] == -1;)
+ k++;
+ if (k < nl) {
+ int i;
+ s->s_accel = NEW(int, nl-k);
+ if (s->s_accel == NULL) {
+ fprintf(stderr, "no mem to add parser accelerators\n");
+ exit(1);
+ }
+ s->s_lower = k;
+ s->s_upper = nl;
+ for (i = 0; k < nl; i++, k++)
+ s->s_accel[i] = accel[k];
+ }
+ DEL(accel);
+}